Driver circuit and display device

ABSTRACT

A display device according to this invention includes: a display panel ( 2 ) having plural pixels configured to display image information; plural driver circuits ( 10 ) configured to drive the plural pixels according to a video signal indicative of the image information which is inputted externally, the video signal being a radio signal; and plural wireless input portions ( 22 ) each configured to obtain a part of the video signal from the radio signal, wherein the plural driver circuits ( 10 ) are each configured to drive a part of the plural pixels according to the part of the video signal obtained by a respective one of the wireless input portions ( 22 ).

RELATED APPLICATION

This application is a national phase of PCT/JP2004/005599 filed on Apr.20, 2004,which claims priority from Japanese Application No. 2003-118239on Apr. 23, 2003, the disclosures of which Applications are incorporatedby reference herein. The benefit of the filing and priority dates if theInternational and Japanese Applications is respectfully requested.

TECHNICAL FIELD

The present invention relates to driver circuits for display devicesand, more particularly, to a driver circuit for high-resolution displaydevices of high display grade including flexible displays (paper-likedisplays), as well as to a display device provided with such a drivercircuit.

BACKGROUND ART

Conventionally, a method such as described below has been generallyemployed to display image information on the display panel of a displaydevice. Initially, an external device (image information processingdevice) transmits desired image information and like information in theform of video signals to a display device through wire. The videosignals thus transmitted are inputted to a driver circuit (driver LSI)configured to drive pixels included in the display panel of the displaydevice via input signal lines. In turn, the driver circuit drives thepixels according to the video signals thus inputted, thereby displayingthe image information on the display panel.

In recent years, such a display device as an electrophoretic display forexample has been under research and development for use as a paper-likethin flexible display or electronic paper. A display device with higherdefinition and higher resolution than conventional liquid displaydevices or like conventional devices is needed to realize a flexibledisplay of high display grade. To this end, a display device of, forexample, active-matrix or passive-matrix type having a very large numberof pixels and display electrodes or signal lines is needed. Such adisplay device has a larger number of semiconductor chips as drivercircuits connected to signal lines or scanning lines than a conventionalone.

In order to realize the aforementioned high-definition andhigh-resolution display, about 3000×(4-8 bits) lines are required as thetotal number of input signal lines connected to the driver circuits forvideo signals for each of the colors, R (red), G (green) and B (blue)for example. In this case, if, for example, 100 chips are mounted as thedriver circuits, the number of input signal lines connected to eachdriver chip is 30×(4-8 bits)×(R, G and B). Thus, a large number of inputsignal lines are required for each driver circuit. For this reason, itbecomes very difficult to mount and handle individual driver circuits,which raises a large problem that mounting and routing for a wholedisplay device becomes complicated and stiffened.

As the display definition has been rendered high in recent years, thenumber of output pins is increased to reduce the number of input linesfor the purpose of avoiding such a mounting problem, which results in adriver LSI having an increased chip size. An LSI chip can be mounteddirectly on glass by COG or a like technique. However, if a large chipis used in a flexible display employing a plastic substrate or a likesubstrate, such a problem is likely that an LSI is broken or a mountingportion is undone.

To avoid complicated routing, video signals are preferably inputtedwirelessly rather than through wire. The flexible display, inparticular, has to meet the requirement that the display be able to behandled like paper while being conveniently rewritable. For this reason,wireless input of video signals to the flexible display is preferable.

Heretofore, a display device wherein an antenna, receiving circuit,driver circuit, display panel and power source are disposed separatelyfrom each other and connected to each other, has been proposed as adisplay device capable of displaying image information based on videosignals wirelessly transmitted to the display device from an externaldevice physically separated from the display device (see, for example,patent literature 1: Japanese Patent Laid-Open Publication No. HEI5-202358 (pp. 24-25 (0071) and FIGS. 2 and 3). As an example of adisplay device thus configured, there has been developed for actual usean active-matrix type liquid crystal display device in which pluraldriver circuits each having multiple input signal lines are disposedbehind an antenna/receiving circuit for wireless input from an externaldevice.

FIG. 10 is a conceptual diagram illustrating the configuration of aconventional wireless input display device. In FIG. 10, an externaldevice (not shown) transmits video signals to display device 80. Thevideo signal thus transmitted are received by antenna 81 and receivingportion 82 and then outputted from the receiving portion 82 to drivercircuit 84 through input signal lines 83. The driver circuit 84 drivespixels of display panel 85 according to the video signals received. Aseparately-provided power source portion 86 supplies electric power todifferent pieces of hardware through power output cable 87 (see patentliterature 1).

The display panel 85 has an array substrate formed with, for example,TFTs (switching elements), pixel electrodes, interconnections and thelike, and a color filter substrate formed with common electrodes. Asdescribed above, color display of image information can be realized bydriving the pixels of the display panel 85 with the driver circuit 84.

The configuration of driver circuit 84 will be described below indetail.

FIG. 11 is a conceptual diagram illustrating the configuration of aconventional driver circuit. Like reference characters are used todesignate like or corresponding parts throughout FIGS. 11 and 10. Asshown in FIG. 11, the driver circuit 84, which is a driver LSIassociated with source signal lines of an active-matrix type displaypanel, comprises a timing generator circuit 88, a sample hold circuit89, and an output buffer circuit 90, which are electricallyinterconnected.

RGB video signals are inputted to the driver circuit 84 via input signallines 83 a. The sample hold circuit 89 samples RGB video signalsinputted within one horizontal scanning period sequentially based onsampling clock signals generated from the timing generator circuit 88.After having been sampled for one horizontal scanning period, the RGBvideo signals are amplified by the output buffer circuit 90 and thenoutputted to the signal lines (source lines) on the display panel 85shown in FIG. 10. On the other hand, the power source portion 86 shownin FIG. 10 supplies the driver circuit 84 with source voltage. Thoughnot shown, a scanning driver circuit (gate driver LSI) outputshorizontal scanning signals to scanning lines (gate lines) on thedisplay panel 85.

In order for such a conventional display device to realizehigh-definition and high-resolution display comparable to that realizedbased on wired input of video signals as described above, it is requiredthat the receiving portion 82 be provided with routing of a total numberof 3000×(4-8 bits)×(R, G and B) input signal lines 83 and, at the sametime, about 100 driver circuit chips 84 each having a number of inputsignal lines 83 a as large as 30×(4-8 bits)×(R, G and B) be mounted.

However, it is very difficult to mount and handle these driver circuits84 individually and, hence, routing for the whole display device 80 iscomplicated and stiffened. That is, the same problem as with wired inputarises even with wireless input. Also, the display device according topatent literature 1 calls for a very high speed receiving circuit LSIfor handling high-frequency signals in realizing high-definition andhigh-resolution display of high display grade based on wireless input.In this case, a large electric power becomes necessary, which raisesanother problem that a high-capacity power source is needed.

For the reasons stated above, a high-definition and high-resolutiondisplay device such as a flexible display is desired to have a drivercircuit requiring as simple routing as possible and to be operable at alow electric power, whether through wire or wirelessly the input ofimage information is made.

Another proposed conventional art is a portable electronic device havinga display portion capable of displaying image information obtained in anon-contact manner. For example, patent literature 2 (Japanese PatentLaid-Open Publication No. 2001-344578 (FIGS. 1,2,9,10 and 11)) hasproposed a portable electronic device including a combination of anon-contact IC card and a display device, wherein a wirelessinput/receive portion comprising an antenna part and an RF part, an ICcard chip portion having a microprocessor and a power source partconfigured to obtain electric power from received signals, a CPUincluding a display driver circuit, and a display device areinterconnected and separately disposed. Such a portable electronicdevice is configured to obtain electric power from signals received bywireless input and hence is capable of realizing wireless transmissionand receipt of data and display of data on the IC card side.

However, even the portable electronic device according to patentliterature 2 needs to be mounted with multiple driver circuits eachhaving a large number of input signal lines for realizinghigh-definition and high-resolution display because the positionalrelation between the wireless input/receive portion, driver circuits andthe display device is the same as in the aforementioned patentliterature 1. In order to obtain electric power from data signalsinputted wirelessly, the portable electronic device according to patentliterature 2 is configured to receive signals at only one wireless inputportion to turn the signals into electric power. Therefore, it ispractically difficult for such a portable electronic device to have ahigh-capacity power source part adapted to wireless input for driving ahigh-definition and high-resolution display device.

As described above, the wireless input portion, receiving portion,display driver circuit and display panel are interconnected andseparately disposed according to any one of the patent literature 1 andpatent literature 2. In order to realize a high-resolution flexibledisplay of high print grade by utilizing these conventional techniques,driver circuits each having a large number of input signal lines need bedisposed and mounted in a larger number than ever. In such a case whereeach driver circuit has a large number of input signal lines, therearises a problem that mounting and handling of such driver circuitsbecomes very difficult.

In the case of the flexible display, an LSI circuit capable ofhigh-speed receiving operation is needed for wireless input of videosignals because the flexible display is of high resolution. Accordingly,the required electric power is increased, which raises a problem that ahigh-capacity power source becomes necessary.

DISCLOSURE OF INVENTION

The present invention has been made in view of the foregoingcircumstances and, therefore, it is an object of the present inventionto provide a driver circuit for display panels which allows easymounting thereof by being not provided with any input signal line, aswell as a display device provided with such a driver circuit.

To attain this object, the present invention provides a display deviceincluding: a display panel having plural pixels configured to displayimage information; and plural driver circuits configured to drive theplural pixels according to a video signal indicative of the imageinformation which is inputted externally, the video signal being a radiosignal; the display device comprising: plural wireless input portionseach configured to obtain a part of the video signal from the radiosignal, wherein the plural driver circuits are each configured to drivea part of the plural pixels according to the part of the video signalobtained by the wireless input portions.

In the display device according to the above-described invention,preferably, each of the plural driver circuits has a respective one ofthe wireless input portions and is configured to drive the part of theplural pixels according to the part of the video signal obtained by therespective one of the wireless input portions.

In the display device according to the above-described invention,preferably, the radio signal is an RF signal; and the wireless inputportions are configured to demodulate the RF signal. In the displaydevice according to the above-described invention, preferably, thewireless input portions of respective of the plural driver circuits areeach configured to receive a respective one of different frequencies.

In the display device according to the above-described invention,preferably, each of the driver circuits further comprises: a storageportion configured to store the part of the video signal therein; asignal transmitting portion configured to modulate the part of the videosignal to generate a transmission signal; and a wireless output portionconfigured to wirelessly output the transmission signal generated by thesignal transmitting portion.

In the display device according to the above-described invention,preferably, the driver circuits are each assigned identificationinformation, and the wireless input portion configured to obtain thepart of the video signal from the radio signal based on theidentification information.

In the display device according to the above-described invention,preferably, the driver circuits are each a large scale integratedcircuit.

In the display device according to the above-described invention,preferably, the driver circuits each comprise a thin film device circuitincluding a thin film transistor.

According to the present invention, there is provided an informationprocessing system comprising: a display device including a display panelhaving plural pixels configured to display image information, and pluraldriver circuits configured to drive the plural pixels according to avideo signal indicative of the image information which is inputtedexternally; and an image information processing device configured totransmit the video signal as a radio signal, wherein: the display deviceincludes plural wireless input portions each configured to obtain a partof the video signal from the radio signal; and the plural drivercircuits are each configured to drive a part of the plural pixelsaccording to the part of the video signal obtained by the wireless inputportions.

In the information processing system according to the above-describedinvention, preferably, each of the plural driver circuits has arespective one of the wireless input portions and is configured to drivethe part of the plural pixels according to the part of the video signalobtained by the respective one of the wireless input portions.

In the information processing system according to the above-describedinvention, preferably, the image information processing device isconfigured to divide the radio signal into plural radio signals andtransmit the plural radio signals at a respective one of differentcarrier frequencies; and the wireless input portions of respective ofthe plural driver circuits are each configured to receive a respectiveone of different frequencies.

In the information processing system according to the above-describedinvention, preferably, the image information processing device isconfigured to transmit a radio signal containing identificationinformation for identifying each of the driver circuits; and thewireless input portion is configured to obtain the part of the videosignal from the radio signal based on the identification information.

According to the present invention, there is provided a display devicedriver circuit for driving a pixel configured to display imageinformation according to a video signal indicative of the imageinformation which is inputted externally, the video signal being a radiosignal, the driver circuit comprising a wireless input portionconfigured to obtain a part of the video signal from the radio signal,the driver circuit being operative to drive the pixel according to thepart of the video signal obtained by the wireless input portion.

In the driver circuit according to the above-described invention,preferably, the radio signal is an RF signal; and the wireless inputportion is operative to demodulate the RF signal.

Preferably, the driver circuit according to the above-describedinvention further comprises a power source portion configured to convertthe received radio signal to electric power energy.

Preferably, the driver circuit according to the above-describedinvention further comprises: a storage portion configured to store thepart of the video signal; a signal transmitting portion configured tomodulate the part of the video signal to generate a transmission signal;and a wireless output portion configured to wirelessly output thetransmission signal generated by the signal transmitting portion.

Preferably, the driver circuit according to the above-describedinvention is assigned identification information, wherein the wirelessinput portion is configured to obtain the part of the video signal fromthe radio signal based on the identification information.

Preferably, the driver circuit according to the above-describedinvention comprises a thin film device circuit including a thin filmtransistor.

The foregoing and other objects, features and advantages of the presentinvention will become apparent from the reading of the followingdetailed description of the preferred embodiments with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram illustrating a configuration of a displaydevice according to embodiment 1 of the present invention.

FIG. 2 is a block diagram illustrating the configuration of a drivercircuit included in a source driver portion of the display deviceaccording to embodiment 1 of the present invention.

FIG. 3 is a block diagram illustrating a detailed configurationincluding a radio signal receiving portion and a power source portion.

FIG. 4 is a conceptual diagram illustrating another configuration of thedisplay device according to embodiment 1 of the present invention.

FIG. 5 is a block diagram illustrating a partial configuration of adriver circuit included in a source driver portion of a display deviceaccording to variation 1 of embodiment 1 of the present invention.

FIG. 6 is a block diagram illustrating a partial configuration of adriver circuit included in a source driver portion of a display deviceaccording to variation 2 of embodiment 1 of the present invention.

FIG. 7A is a plan view illustrating a configuration of a display deviceaccording to embodiment 2 of the present invention.

FIG. 7B is a sectional view illustrating a configuration of the displaydevice according to embodiment 2 of the present invention.

FIG. 8 is a conceptual diagram illustrating a configuration of aninformation processing system including the display device according toembodiment 2 of the present invention.

FIG. 9 is a conceptual diagram illustrating another configuration of theinformation processing system including the display device according toembodiment 2 of the present invention.

FIG. 10 is a conceptual diagram illustrating a configuration of aconventional wireless input display device.

FIG. 11 is a conceptual diagram illustrating a configuration of aconventional driver circuit.

FIG. 12 is a sectional view illustrating the construction of a CMOStransistor fabricated by the low-temperature polysilicon technology.

FIG. 13 is a circuit diagram of an inverter serving as a basis for alogic circuit forming a driver circuit.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings.

Embodiment 1

FIG. 1 is a conceptual diagram illustrating a configuration of a displaydevice according to embodiment 1 of the present invention. As shown inFIG. 1, display device 1 comprises, at least, an active-matrix typedisplay panel 2 configured to display image information, a source driverportion 3 configured to output video signals within one horizontalscanning period to drive pixels, a gate driver portion 4 configured tooutput horizontal scanning signals sequentially, and a timing controlcircuit 5 configured to generate clock signals and horizontal andvertical synchronizing signals and then output them to the source driverportion 3 and gate driver portion 4.

The display panel 2 may comprise, for example, an electrophoreticdisplay panel having an electrophoretic display material interposedbetween an array substrate 6 and a non-illustrated color filtersubstrate which are positioned to face each other, the electrophoreticdisplay panel being of the memory display type. The display panel 2 maycomprise any other display panel than the electrophoretic display panelwhich can be used as a flexible display.

In the display panel 2 a plurality of signal lines (source lines) 7connected to the source driver portion 3 and a plurality of scanninglines (gate lines) 8 connected to the gate driver portion 4 are arrangedto intersect each other. Though not shown, a TFT (switching element)fabricated by the low-temperature polysilicon technology and a pixelelectrode comprising a transparent electrode, an Al reflective electrodeor a like electrode are provided at each point of intersection 9. Thus,each of the pixels defined by the signal lines 7 and the scanning lines8 is provided with a switching element and a pixel electrode. Also,though not shown, common electrodes are formed on the color filtersubstrate opposed to the array substrate 6.

In the source driver portion 3 are disposed plural signal-side drivercircuits 10 configured to output RGB video signals for driving thepixels, the RGB video signals each forming part of a video signalindicative of image information. In this embodiment about 100 driverLSIs (large scale integrated circuits), each of which has a small chipform, are disposed as the driver circuits 10 for high-precision andhigh-resolution display. Signal output terminals (not shown) of thesedriver circuits 10 are each connected to a respective one of the signallines 7.

In the gate driver portion 4 are disposed plural scanning-side drivercircuits (driver LSIs) 11. Scanning signal output terminals (not shown)of these driver circuits 11 are each connected to a respective one ofthe scanning lines 8.

In the display device 1 thus configured, the timing control circuit 5outputs a control signal to each of the source driver portion 3 and thegate driver portion 4 according to a video signal inputted externally.Thus, the driver circuits 11 of the gate driver portion 4 outputscanning signals to the scanning lines 8 to turn on the switchingelements of respective pixels sequentially, while on the other hand thedriver circuits 10 of the source driver portion 3 input video signals tothe pixels sequentially via the signal lines 7 in a manner timed to theoperation of the driver circuits 11. As a result, the pixels are drivento display image information on the display panel 2.

Description will be made of a detailed configuration of each of thesignal-side driver circuits 10 included in the source driver portion 3.

FIG. 2 is a block diagram illustrating the configuration of each drivercircuit 10 included in the source driver portion 3 of the display device1 according to embodiment 1 of the present invention.

As shown in FIG. 2, driver circuit 10 includes: a radio signal receivingportion A having a wireless input portion 22 for inputting video signalswhich are radio signals R and a signal receiving portion 23; a signalprocessing portion 24 configured to process the video signals outputtedfrom the radio signal receiving portion A; and a timing generatorcircuit 26 and a signal output portion 25 which are connected to thesignal processing portion 24.

The driver circuit 10 further includes a power source portion 31, to bedescribed later, connected to the wireless input portion 22.

The wireless input portion 22 of the driver circuit 10 thus configuredreceives an RF signal (radio frequency signal) indicative of imageinformation transmitted from an image information processing device (notshown) as an external device, the RF signal being a radio signal Rresulting from sequential and/or parallel modulation of carrierfrequency. In this case the wireless input portion 22 receives a part ofthe RF signal according to one predetermined received frequency and thenoutputs the received signal to the signal receiving portion 23.

The signal receiving portion 23 demodulates the received signal inputtedfrom the wireless input portion 22 and then outputs the demodulatedsignal as received data forming part of the RGB video signal to thesignal processing portion 24. The signal processing portion 24, in turn,performs signal processing on the received data inputted and thenoutputs the processed data as signal data to the signal output portion25.

To the timing generator circuit 26 are inputted a basic clock signalsent thereto from the timing control circuit 5 via a clock signalterminal 27, and horizontal and vertical synchronizing signals sentthereto from the timing control circuit 5 via a horizontal and verticalsynchronizing signal input terminal 28. The timing generator circuit 26outputs a synchronizing signal to other driver circuit 10 locatedadjacent to the driver circuit 10 of concern via a synchronizing signaloutput terminal 29 and an output clock signal to the signal outputportion 25. On the other hand, a sample hold circuit (not shown)provided in the signal processing portion 24 sequentially samples theaforementioned received data inputted within one horizontal scanningperiod according to the clock signal outputted from the timing generatorcircuit 26. Thereafter, the received data thus sampled is outputted assignal data from the sample hold circuit to the signal output portion25. In turn, an output buffer circuit (not shown) provided in the signaloutput portion 25 amplifies the signal data. The signal data thusamplified is outputted to the signal lines 7 of the display panel 2 viasignal output terminals 30.

The power source portion 31 obtains the received signal from thewireless input portion 22 and converts the received signal to sourcevoltage (energy) to obtain electric power required to operate the insidecomponents of the driver circuit 10.

As described above, the driver circuit 10 receives the input of a videosignal wirelessly and outputs signal data to the display panel 2.

With reference to FIG. 3, description will be made of a detailedconfiguration including the radio signal receiving portion A providedwith the above-described wireless input portion 22 and signal receivingportion 23, and the power source portion 31.

As shown in FIG. 3, the wireless input portion 22 of the radio signalreceiving portion A is formed into an antenna comprising coil 32 andcapacitor 34. However, the wireless input portion 22 is not limited tothis form but may be in any form which is capable of wireless input. Thewireless input portion 22 detects and tunes the RF signal indicative ofimage information which has resulted from sequential and/or parallelmodulation of the carrier frequency and transmitted wirelessly from theimage information processing device.

The signal receiving portion 23 includes an A/D converter portion 35 anda signal demodulator portion 36. The received analog signal obtainedaccording to one predetermined received frequency by the wireless inputportion 22 is converted to a digital signal by the A/D converter portion35 of the signal receiving portion 23. The signal demodulator portion 36demodulates the digital signal to obtain the received data comprising anRGB video signal is obtained. The received data thus obtained isoutputted from the signal receiving portion 23 to the signal processingportion 24.

Also, as shown in FIG. 3, a rectifier circuit 37 is provided between thewireless input portion 22 and the power source portion 31. The rectifiercircuit 37 rectifies the received signal inputted via the wireless inputportion 22 and then outputs the received signal thus rectified to thepower source portion 31.

The power source portion 31 converts the received signal outputted fromthe wireless input portion 22 to electric power energy as d.c. sourcevoltage (VDD, VSS) by using a non-illustrated smoothing capacitor andthen supplies the electric power energy to each inside component of thedriver circuit 10.

The power source portion 31 is not limited to the above-describedconfiguration but may be of any configuration which is capable ofconverting the received signal outputted from the wireless input portion22 to electric power energy.

By thus causing the power source portion 31 in the driver circuit 10 togenerate electric power for driving the driver circuit 10, the powersource portions 31 can cooperatively supply the electric power requiredto drive the whole display device 1. It is needless to say that such aconfiguration is possible that a power source portion is provided withinthe driver circuit 10 for supplying electric power energy to the drivercircuit 10 and the power source portion 31 assists the power sourceportion in supply of electric power energy.

Since the driver circuit 10 inputs the video signal wirelessly asdescribed above, an input signal line for the video signal outputtedfrom an external device becomes unnecessary. For this reason, themounting of the driver circuit 10 becomes easy. As a result, themounting portion of the driver circuit 10 can be rendered compact in thepaper-like display device 1 capable of high-definition andhigh-resolution display. What is more, the LSI chip constituting thedriver circuit 10 has a small form and hence is difficult to break. As aresult, display failure of the display panel 2 is not likely to occureven when the whole display device 1 is bent.

Also, each driver circuit 10 obtains only part of image informationrequired for the display device 1 by wireless input. Thus, the sourcedriver portion 3, as a whole, obtains the whole of the imageinformation. With such a feature, the signal frequency handled by eachdriver circuit 10 can be lowered and, therefore, electric power of thesame level as required by a conventional driver circuit not adapted tohigh-definition and high-resolution display is sufficient for the driver10.

As described above, each driver circuit 10 receives a part of thereceived signal, which is an RF signal (radio frequency signal)indicative of image information wirelessly transmitted thereto andresulting from sequential and/or parallel modulation of the carrierfrequency, from the external image information processing device (notshown) using wireless input portion 22 of which the received frequencyis different from that of the wireless input portion of other drivercircuit 10. Each of the driver circuits 10 obtain part of the imageinformation from the part of received signal using the signal receivingportion 23 and then outputs the part of image information to arespective one of the signal lines 7 of the display panel 2. The pixelsof the display panel 2 are driven by output signals from respectivedriver circuits 10 of the source driver portion 3 and scanning signalsfrom respective driver circuits 11 of the gate driver portion 4, wherebydesired image information is wholly displayed on the display panel 2.

By thus dividedly inputting the received signal required for the imageinformation to be wholly displayed to the driver circuits, it ispossible to realize a display device capable of high-definition andhigh-resolution display at a low electric power.

In the case of driver circuit 10 according to the present embodiment,both the wireless input portion 22 and the signal output portion 25 fordriving pixels are incorporated in one LSI. However, the presentinvention is not limited to this configuration. For example, as shown inFIG. 4, driver circuit 10 may be formed by connecting an LSI 80including at least a wireless input portion (not shown) and a signalreceiving portion (not shown) to plural LSIs 81 each including at leasta signal output portion (not shown). FIG. 4 shows a configurationwherein driver circuits 10 are formed on a block basis, each drivercircuit 10 comprising one block having one LSI 80 and three LSIs 81. Theconfiguration has a smaller number of routed wires than a conventionalconfiguration having one wireless receiving circuit, though the numberof routed wires is larger than that of the configuration described withreference to FIG. 1. Further, shared processing on a block basisprovides the effect of reducing the load on the wireless circuit.

Variation 1

FIG. 5 is a block diagram illustrating a partial configuration of adriver circuit included in a source driver portion of a display deviceaccording to variation 1 of embodiment 1 of the present invention. Likereference characters are used to designate like or corresponding partsthroughout FIG. 5 and FIGS. 2 and 3 illustrating the present embodiment.

The display device according to variation 1 is different from thedisplay device shown in FIGS. 1 and 3 in that the display deviceincludes a signal transmitting portion 41 in radio signal receivingportion A of wireless input driver circuit 10, a storage portion (buffermemory) 42 in signal processing portion 24, and a wireless outputportion 46.

The storage portion 42 is configured to store received data, which isvideo signal data outputted from the signal receiving portion 23. Samplehold circuit 43 in the signal processing portion 24 performspredetermined signal processing on the received data inputted from thestorage portion 42.

The signal transmitting portion 41 includes a signal modulator portion44 and a drive 45. Video signal data outputted from the storage portion42 of the signal processing portion 24 is inputted as transmitted datato the signal transmitting portion 41. The signal modulator portion 44of the signal transmitting portion 41 modulates the transmitted datainputted thereto into a transmission signal, which in turn is amplifiedby the drive 45 and then wirelessly outputted as part of imageinformation from the wireless output portion 46 which is an antenna alsoserving as the wireless input portion 22. The wireless output portion 46may be provided separately from the wireless input portion 22 withoutsharing the antenna.

Each driver circuit 10 is assigned its own identification informationsuch as an identification number and stores ID code data indicative ofits own identification information in a predetermined storage portion.By outputting such ID code data together with a video signal when theimage information processing device or other display device outputs thevideo signal, the video signal can be properly transmitted to andreceived from the image information processing device or other displaydevice and the driver circuit 10 identified by the specified ID codedata. Also, the image information processing device can transmit imageinformation to only the specific driver circuit 10 identified by ID codedata specified and update only an associated portion of screen. Thus,the time and electric power required for updating of an image can bereduced. This effect is advantageous particularly to a non-volatiledisplay system such as an electrophoretic display system.

Variation 2

FIG. 6 is a block diagram illustrating a part of another configurationof a driver circuit included in a source driver portion of a displaydevice according to embodiment 1 of the present invention. Likereference characters are used to designate like or corresponding partsthroughout FIG. 6 and FIG. 5 illustrating variation 1.

The driver circuit included in the display device according to variation1 includes the storage portion in the signal processing portion, asshown in FIG. 5. On the other hand, a driver circuit included in thedisplay device according to variation 2 includes storage portion 42 inradio signal receiving portion A.

In the driver circuit of the display device according to variation 2,signal receiving portion 23 outputs received data, which is video signaldata, to signal processing portion 24 while causing storage portion 42of driver circuit 10 to store the received data therein.

Signal transmitting portion 41 inputs thereto the video signal datastored in the storage portion 42 as transmitted data, modulates andamplifies the transmitted data, and outputs a transmission signal towireless output portion 46. The wireless output portion 46, in turn,wirelessly outputs the transmission signal as part of image information.

As described above, the driver circuit of the display device accordingto variation 1 or 2 can read out video signal data stored in the storageportion provided within the driver circuit as transmitted data andoutput part of image information wirelessly (in the form of RF signal).Thus, it becomes possible to wirelessly output the image informationshared for display by driver circuits to the image informationprocessing device or other display device.

In the above-described embodiment, each of driver circuit 10 of sourcedriver portion 3 and driver circuit 11 of gate driver portion 4 has beendescribed to comprise an LSI (large scale integrated circuit). Such adriver circuit may comprise a thin film device circuit including atleast a TFT (thin film transistor) formed by the thin film growthprocess such as the low-temperature polysilicon technology. With thethin film growth process for forming TFTs as switching elements, pixelelectrodes, interconnections and the like on array substrate 6, it ispossible to form at least driver circuits 10 and 11 and array substrate6 by one process step.

FIG. 12 is a sectional view illustrating the construction of a CMOStransistor fabricated by the low-temperature polysilicon technology. Asshown in FIG. 12, the CMOS transistor comprises a p-type transistor 100and an n-type transistor 101. The CMOS transistor shown in FIG. 12includes, on an insulating substrate 102 such as of glass, source 103and drain 105 formed by doping a silicon thin film renderedpolycrystalline by excimer laser annealing with boron, source 106 anddrain 108 doped with phosphorus, and channel layers 104 and 107. In then-type transistor 101, LDD regions 109 and 110, which are doped lightly,are formed on the insulating substrate 102. Gate oxide films 111 and 112each comprising silicon nitride and gate electrodes 113 and 114 eachcomprising stacked films of titanium and aluminum, are stacked thereon.An insulating film 115 has openings in which lead electrodes 116contacting source and drain are formed. Cap layers 117 and 118 arestacked to cover these components. By connecting such p-type transistorand n-type transistor to each other, each of driver circuits 10 and 11according to the present invention can be realized which comprises athin film device circuit including a thin film transistor. FIG. 13 is acircuit diagram of an inverter serving as a basis for a logic circuitforming driver circuit 10,11 thus realized.

If such a driver circuit thus formed using a TFT includes an inductanceprovided by forming each of gate and source wires into a plane coil inaddition to a transistor and capacitor as used in a liquid crystaldisplay, the above-described driver circuit for the display deviceaccording to the present embodiment can be realized.

Meanwhile, the carrier mobility of a TFT is as low as about ⅕ of that ofan LSI and hence has a drawback that it cannot accommodate to highfrequencies. However, the present invention can lower a frequency to behandled by the provision of plural driver circuits. Therefore, thepresent invention has an advantage that driver circuits each using a TFTcan be easily realized even in a high-definition display. As a result,it becomes possible to form a display device which does not need anywiring connecting to outside by the TFT process only.

Embodiment 2

FIG. 7A is a plan view illustrating a configuration of a display deviceaccording to embodiment 2 of the present invention and FIG. 7B is asectional view of the configuration. As shown in FIGS. 7A and 7B, awireless input antenna portion 61 for display device and a power sourceportion 62 for display device are provided on the reverse side of arraysubstrate 6 included in a display device 60. A received signal obtainedvia the wireless input antenna portion 61 is converted to electric powerenergy (source voltage) by the power source portion 62.

In the display device 60 thus configured, the power source portion 62for display can supply electric power to the driver circuits 10 and 11and the like or assist in the supply of electric power thereto, therebydriving the driver circuits 10 and 11 and the like.

It should be noted that like reference characters are used to designatelike or corresponding parts throughout embodiment 2 and embodiment 1 toomit description thereof.

In the case of display device 60 according to embodiment 2, a receivedsignal is obtained through the wireless input antenna portion 61 fordisplay device and then converted to source voltage by the power sourceportion 62 for display device, whereby insufficient supply of electricpower to the display device 60 can be supplemented. As a result, thedisplay device capable of wireless input and output can be operatedstably. Particularly, wireless output requires large power consumptionand hence is highly likely to make the operation of the display deviceunstable. In view of this, stabilizing the operation of the displaydevice is considered to be of great significance.

Description will be made of an information processing system includingdisplay device 60 according to embodiment 2.

FIG. 8 is a conceptual diagram illustrating a configuration of aninformation processing system including the display device 60 accordingto embodiment 2 of the present invention. Like reference characters areused to designate like or corresponding parts throughout FIG. 8 and FIG.7.

As shown in FIG. 8, information processing system 70 includes imageinformation processing device 71 and display device 60.

As described above, the power source portion 62 for display supplieselectric power to the driver circuits 10 and 11 and the like or assistsin the supply of electric power thereto, thereby driving the drivercircuits 10 and 11 and the like.

Driver circuits 10 included in source driver portion 3 receive imageinformation modulated sequentially and/or in parallel by carrierfrequencies f1, f2, . . . , fin and wirelessly transmitted from theimage information processing device 71. For convenience of description,the driver circuits 10 for receiving respective image information itemstransmitted by carrier frequencies f1, f2, . . . , fn will be referredto as driver circuits D1, D2, . . . , Dn, respectively. Pixels ofdisplay panel 2 are driven by output signals which are video signalsfrom the driver circuits D1, D2, . . . , Dn and scanning signals fromdriver circuits 11, thereby to display the whole of desired imageinformation on the display panel 2.

Each of the driver circuits D1, D2, . . . , Dn capable of wirelessoutput in this way reads out video signal data stored in a storageportion provided therein as transmitted data. Then, each of the drivercircuits D1, D2, . . . , Dn modulates the transmitted data into arespective one of the carrier frequencies f1, f2, . . . , fn and outputspart of the image information wirelessly. Thus, the display device 60can transmit the whole or part of high-definition image information tothe image information processing device 71 or other display device.

In the case of the above-described information processing system 70,wireless communication of image information between the imageinformation processing device 71 and the display device 60 becomespossible by the image information processing device 71 and displaydevice 60 wirelessly transmitting and receiving video signals obtainedby sequential and/or parallel modulation of image data into carrierfrequencies to and from each other.

The image information processing device 71 is a device comprising, atleast, means of generating image information to be displayed orobtaining the image information externally, and means of wirelesslytransmitting image information. For example, either a mobile device suchas a personal computer or a PDA or other device such as an informationtransmitting device can be used as the image information processingdevice 71. The display device 60 receives image information wirelesslyoutputted from the image information processing device 71, therebyrealizing the information processing system 70 which enables the viewerto view a high-definition screen at hand.

It is to be noted that the image information processing device 71 andthe display device 60 are not necessarily independent of each other butmay be components of a single device. For example, among variousconventional mobile devices, there is one which employs a foldableflexible substrate for electrical connection between, for example, adisplay panel and other components in order to reduce its size. In sucha case highly complicated routing of wires is necessary. Suchcomplicated routing becomes unnecessary if a mobile device includesdisplay device 60 and image information processing device 71 fortransmitting image information to the display device 60, which devices60 and 71 are configured to transmit and receive image information toand from each other. As a result, the mobile device can be reduced insize and simplified in structure, which leads to a reduction in cost.

FIG. 9 is a conceptual diagram illustrating another configuration of theinformation processing system including the display device 60 accordingto embodiment 2 of the present invention. Like reference characters areused to designate like or corresponding parts throughout FIG. 9 and FIG.7.

As shown in FIG. 9, information processing system 70 includes pluralimage information processing devices 71 and plural display devices 60.Each of driver circuits 10 (hereinafter will be referred to as drivercircuits D1, D2, . . . , Dn as in the above-described case) included inthe source driver portion of each of the display devices 60 is assignedits own identification information. Each of the driver circuits D1, D2,. . . , Dn stores ID code data item indicative of its own identificationinformation in a predetermined storage portion.

Each of the image information processing devices 71 modulates imageinformation sequentially and/or in parallel by carrier frequencies f1,f2, . . . , fn and wirelessly transmits modulated image informationitems together with specific ID code data items. In this case each ofthe driver circuits D1, D2, . . . , Dn receives an image informationitem attached with an ID code data item identical with the ID code dataitem previously assigned thereto. Pixels of display panel 2 are drivenby video signals outputted from the driver circuits D1, D2, . . . , Dnand scanning signals outputted from driver circuits 11, thereby todisplay the whole of desired high-definition and high-resolution imageinformation on the display panel 2.

In each display device 60 each of the driver circuits D1, D2, . . . , Dnreads out video signal data stored in a storage portion (not shown)provided therein as transmitted data. Then, the driver circuits D1, D2,. . . , Dn each modulate the transmitted data into a respective one ofthe carrier frequencies f1, f2, . . . , fn and each wirelessly outputpart of the image information together with a respective one of the IDcode data items of their own. Thus, each display device 60 can transmitand receive the whole or part of high-definition image information toand from each image information processing device 71 or other displaydevice 60 properly without any error.

In the case of the above-described information processing system 70,since the driver circuits 10 of each display device 60 have their own IDcode data items, each image information processing device and eachdisplay device become possible to transmit and receive video signals toand from each other without any error. Also, each image informationprocessing device can transmit image information to only the specificdriver circuit 10 identified by an ID code data item specified andupdate only an associated portion of screen. Thus, the time and electricpower required for updating of an image can be reduced. This effect isadvantageous particularly to a non-volatile display system such as anelectrophoretic display system.

Of course, it is possible for the above-described method to establishsuch settings that communication of image information is inhibitedbetween image processing devices and display devices having either agroup of IDs other than specified ID code data items or driver circuitsidentified by ID code data items other than the specified ID code dataitems, hence, exchange of information is impossible therebeween.

Though description has been made of the display device employing displaydevice driver circuits capable wireless input and output and theinformation processing system including the display device employingsuch driver circuits, use of driver circuits capable of only wirelessinput makes it possible to embody the present invention as a displaydevice and an information processing system which transmit imageinformation only one way.

While the display device according to any one of the foregoingembodiments is configured to receive analog signals modulated andcarried by radio frequencies, perform A/D conversion and thendemodulation, and carry out digital processing on the demodulatedsignals, the present invention may be embodied as a digital-signaldisplay device which is configured to receive digital signals modulatedand carried by radio frequencies, demodulate the signals without A/Dconversion, and carry out digital processing on the demodulated signals.

While an active-matrix type display device has been described as thedisplay device of the present invention in any one of the foregoingembodiments, it is needless to say that the display device of thepresent invention may be a passive-matrix type (simple-matrix type)display device.

Also, while an electrophoretic display panel (EPID) has been describedas a flexible display panel in any one of the foregoing embodiments, itis possible to employ any one of memory display type display panelsincluding a liquid-phase EPID, liquid crystal display panel (LCD),electrochromic display panel (ECD), electrodeposition display panel anda like display panel, or any one of non-memory display type displaypanels including a liquid crystal display panel (LCD), organicelectroluminescent display panel (organic EL) and a like display panel.

The display device of the present invention is not limited to a flexibledisplay but may be a display of glass such as a conventional LCD.

It will be apparent from the foregoing description that manyimprovements and other embodiments of the present invention may occur tothose skilled in the art. Therefore, the foregoing description should beconstrued as an illustration only and is provided for the purpose ofteaching the best mode for carrying out the present invention to thoseskilled in the art. The details of the structure and/or the function ofthe present invention can be modified substantially without departingfrom the spirit of the present invention.

INDUSTRIAL APPLICABILITY

The driver circuit and the display device according to the presentinvention are useful as a driver circuit for display devices required toprovide high-definition and high-resolution display and as such adisplay device.

1. A display device including: a matrix type display panel provided withplural pixels configured to display image information by a plurality ofsignal lines and a plurality of scanning lines which are provided on asubstrate such that the plurality of signal lines and the plurality ofscanning lines cross each other; and plural driver circuits configuredto drive the plural pixels according to a video signal indicative of theimage information which is inputted externally, the video signal being aradio signal; the display device comprising: plural wireless inputportions each configured to obtain a part of the video signal from theradio signal, wherein the plural driver circuits are each configured todrive apart of the plural pixels according to the part of the videosignal obtained by the wireless input portions.
 2. The display deviceaccording to claim 1, wherein each of the plural driver circuits has arespective one of the wireless input portions and is configured to drivethe part of the plural pixels according to the part of the video signalobtained by the respective one of the wireless input portions.
 3. Thedisplay device according to claim 1, wherein: the radio signal is an RFsignal; and the wireless input portions are configured to demodulate theRF signal.
 4. The display device according to claim 3, wherein thewireless input portions of respective of the plural driver circuits areeach configured to receive a respective one of different frequencies. 5.The display device according to claim 1, wherein each of the drivercircuits further comprises: a storage portion configured to store thepart of the video signal therein; a signal transmitting portionconfigured to modulate the part of the video signal to generate atransmission signal; and a wireless output portion configured towirelessly output the transmission signal generated by the signaltransmitting portion.
 6. The display device according to claim 2,wherein the driver circuits are each assigned identificationinformation, and the wireless input portion configured to obtain thepart of the video signal from the radio signal based on theidentification information.
 7. The display device according to claim 1,wherein the driver circuits are each a large scale integrated circuit.8. The display device according to claim 1, wherein the driver circuitseach comprise a thin film device circuit including a thin filmtransistor.
 9. An information processing system comprising: a displaydevice including: a matrix type display provided with plural pixelsconfigured to display image information by a plurality of signal linesand a plurality of scanning lines which are provided on a substrate suchthat the plurality of signal lines and the plurality of scanning linescross each other; and plural driver circuits configured to drive theplural pixels according to a video signal indicative of the imageinformation which is inputted externally; and an image informationprocessing device configured to transmit the video signal as a radiosignal, wherein: the display device includes plural wireless inputportions each configured to obtain a part of the video signal from theradio signal; and the plural driver circuits are each configured todrive a part of the plural pixels according to the part of the videosignal obtained by the wireless input portions.
 10. The informationprocessing system according to claim 9, wherein each of the pluraldriver circuits has a respective one of the wireless input portions andis configured to drive the part of the plural pixels according to thepart of the video signal obtained by the respective one of the wirelessinput portions.
 11. The information processing system according to claim10, wherein: the image information processing device is configured todivide the radio signal into plural radio signals and transmit theplural radio signals at a respective one of different carrierfrequencies; and the wireless input portions of respective of the pluraldriver circuits are each configured to receive a respective one ofdifferent frequencies.
 12. The information processing system accordingto claim 10, wherein: the image information processing device isconfigured to transmit a radio signal containing identificationinformation for identifying each of the driver circuits; and thewireless input portion is configured to obtain the part of the videosignal from the radio signal based on the identification information.13. A display device driver circuit for driving a pixel configured todisplay image information according to a video signal indicative of theimage information which is inputted externally, the video signal being aradio signal, the driver circuit comprising a wireless input portionconfigured to obtain a part of the video signal from the radio signal,the driver circuit being operative to drive the pixel according to thepart of the video signal obtained by the wireless input portion.
 14. Thedriver circuit according to claim 13, wherein: the radio signal is an RFsignal; and the wireless input portion is operative to demodulate the RFsignal.
 15. The driver circuit according to claim 13, further comprisinga power source portion configured to convert the received radio signalto electric power energy.
 16. The driver circuit according to claim 13,further comprising: a storage portion configured to store the part ofthe video signal; a signal transmitting portion configured to modulatethe part of the video signal to generate a transmission signal; and awireless output portion configured to wirelessly output the transmissionsignal generated by the signal transmitting portion.
 17. The drivercircuit according to claim 13, which is assigned identificationinformation, wherein the wireless input portion is configured to obtainthe part of the video signal from the radio signal based on theidentification information.
 18. The driver circuit according to claim13, which comprises a thin film device circuit including a thin filmtransistor.
 19. The display device according to claim 1, wherein thesubstrate is a flexible substrate.